Khyzer Ahmed Sheikh - National University of Sciences and Technology, Islamabad, Pakistan
Ahsan Saif - National University of Sciences and Technology, Islamabad, Pakistan

Most slope stability analyses are carried out in two dimensional and consider plane strain conditions, which may favor slope design, but it is not representative of site conditions when slope geometry and pore water conditions are complex and material properties vary over the width of slope. Translational landslides have large difference in the mobilized shear strength on the end vertical sides and back scarp as compared to the base of the failure surface which produce significant differences in ۳D and ۲D analyses. This introduces a deficiency in the analysis of translational landslides as the current available ۳D Limit Equilibrium (LE) slope analysis software does not incorporate shear resistance provided by the end vertical sides during slope failure. As a consequence, ۳D factor of safety is underestimated, and back calculated shear strength of the soil is overestimated. In order to incorporate side shear resistance in ۳D stability analyses, different researchers proposed different methods for this purpose. This paper describes the importance of ۳D analysis and end shear side resistance in slope analyses of Translational landslides through case studies and discusses the different methods for incorporating side resistance in ۳D LE analysis to make analysis of translational slides more accurate and practically applicable.

۳D Slope stability, Translational landslide, ۳D Side resistance, ۳D Factor of safety, Slope stability case study